Pollution is the introduction of contaminants into the natural environment that cause adverse changes. The document discusses different types of pollution including air, land, noise, and water pollution. Air pollution is caused by particles, gases, and biological molecules in the atmosphere that can harm health. Land pollution results from improper waste disposal or chemicals used in agriculture. Noise pollution comes from machines, vehicles, and construction activities. Water pollution contaminates bodies of water and damages ecosystems and species. The causes of pollution include using natural resources faster than they can replenish, overindustrialization, and excessive use of chemicals in industry and agriculture.